Blasting cartridge



March 12, 1929. H. s. HART 12,705,248

BLAS TING CARTRIDGE Filed Oct. l, 1927 12,089 of 1889 and in the United States Patented Mar. 12, 1929.

HARRY s. naar, on cmcneo, ILLINoIs BLASTING CARTRIDGE.

Application med october 1, 1927. serial No. 223,262.

My invention relates more particularlyto apparatus for blasting coal or other material capable of being brought down by blasting methods in mines as shown and described for example in the British patent to Gift'ard Np. Pa ent to Ferrell, Helmholtz and Crawford N o. 1,632,887 dated June 21st, 1927, and has fior its object to provide an improved means ior blasting in which the sudden ex ansion of carbon dioxide in solid or liquid orm causes an explosion of gas directly through. the lon-- gitudinal wall of the cartridge and 1n transverse direction therefrom. Other and further objects will appear hereinafter.

In the accompanying drawings, Fig. lis

a longitudinal section illustrating one embodiment of my invention. Figs. 2, 3 and 4 are cross sections on the line 2-2 of Fig. 1, showinglvarious possible arrangements ofthe weakened portions of the wall. Fig. 5 1s a longitudinal section of a portion of a cartridge showing a modified form of my invention. Fig. 6 is a longitudinal section of a portion of a cartridge showing another moditication. Fig. 7 is a front elevation illustrating a wall of coal in the mine, with my improved cartridges arranged ready for blasting. Fig. 8 is a longitudinal section-on the line' 8 8 of Fig. 7.

In the use of carbon dioxide for blasting purposes it is desirable that the expansive effort of the gasiied carbon dioxide be such that the tendency for the cartridge to recoil is lessened and that at the same time the expansion shall take place in a direction to bring down the material in large blocks without the production vof dust or iine material and that to this end the expansion be initiated in a predetermined direction.

In the embodiment of my invention illustrated I provide a cylindrical metallic casing as shown in the drawings in which A`is the cylindrical longitudinal wall of the cartridge closed at each end by end walls C, which may be rigidly attached to the longitudinal cylindrical wall A in, any preferred manner, as

for example, by the screw threads shown in Fig. 1. Within this casing is placed a light metallic casing D containing a suitable explosive adapted to be ignited through electrical connections lil-E. Carbon dioxide in the non-gaseous state, i. e., liquid or solid carbon dioxide, fills the remainder of the cartridge. The walls A and C of the cartridge are of suiicient strength to resist a predetermined pressure of the carbon dioxide gas when the liquid or solid carbon dioxide is gas'lied by the action of the explosive in the casing D except at certain weakened portions of the wall A. These weakened portions, as illustrated in Fig. 1, may be formed by reducing the thickness of the wall at such points as it is desired to be ruptured when the predetermined pressure is reached upon gasification of the carbon dioxide.

By reference to Figs. 2, 3 and 4, it will be noted that these weakened portions may be arranged at any desired point in the wall. In Fig. 2 they are shown at four points in the circumference of the wall so that upon rupture of all the weakened portions the expanding gas will be directed in four ways. In Fig. 3 they are shown at two' points in this wall so that the gas will expand in two directions at right. angles to each other. In Fig., 4 there is a single weakened portion, permitting the expansion ofthe gas in a single direction. While I have shown in Fig. 1 these weakened portions as formed at intervals along the length of the longitudinal wall, it is obvious that the weakened portions may be located at one end only, at two ends, or at the middle, or in fact at any selected point or points on this longitudinal wall.

Fig. 5 illustrates a modification of the invention showing a different method of forming the weakened portions of the wall. In this case, an opening is made through the wall in which opening is screwed a plug B containing a plate B of less thickness than the longitudinal wall A and consequently weaker. Fig. 6 shows another modification in which the wall A is provided with an opening B and the carbon dioxide is enclosed in a metallic casing F closely fitted to the bore of the cartridge, the explosive casing D being contained withinthe casing F. At the points B the wall of this interior casing forms a weakened portion through which, upon rupture, the gasified carbon dioxide escapes as above described.

In Figs. 7 and 8 I have illustrated a method of using my cartridges. In these figures G represents the wall of coal to be brought down in the mine and the cartridges provided with the proper weakened portions may be arranged as here shown. For example, at the corners I place the cartridges A provided with the weakened portions at right angles to each other as illustrated in Fig. 3. The explosion from these cartridges being trans-` verse with respect to 'the body of the cartridge and issuing directly from this body will be horizontal and vertically downward with respect to the body of coal to be brought down. In like manner at the intermediate points I place cartridges with the weakened portions arranged at three points so that the intermediate cartridges in the upper and lower horizontal lines will direct a horizontal explosion toward the corner cartridges and a vertical explosion through the body of the coal, while 'the intermediate cartridges in the vertical lines will direct a vertical explosion toward the corners and a horizontal explosion through the body of the coal. It will be understood, however, that any .suitable or desirable arrangment of the cartridges may be made. l

It will be seen from the above description that I have provided a cartridge in which the gas under high pressure emerges directly from the longitudinal wall of the cartridge and crosswise or transversely with respect thereto, thus making it possible to direct the explosive force of the gas in any desired direct-ion into the coal body and in such a manner that it may readily seek passage through the crevices existing in the coal body, reducing the tendency of the cartridge to recoil which exists Where carbon dioxide is shot longitudinally through the cartridge and without the shattering of the entire body of the l. A blasting cartridge comprising a rigid casing, a charge of carbon dioxide in the nongaseous state in the casing, means for raising the temperature of the carbon dioxide to and above the critical temperature of non-gaseous carbon dioxide, and rupturable means at a predetermined point in the Wall of the cartridge permitting the escape of gaseous car-v bon dioxide at a predetermined pressure and in -transverse direction with respect to the casing.

2. A blasting cartridge comprising a casing having walls of a strength to resist the pressure of gasiiied carbon dioxide coniined therein except at predetermined points, a Wall of the cartridge being provided with weakened portions at such points, said weakened port-ions being located in the wall so as to permit the escape of the gasiiied carbon dioxide upon rupture of the weakened portions in a direction transverse with respect to the casing. i

HARRY S. HART. 

